What about the ones under the Newbridge roundabout?

They were put in when the M8 was rebuilt to go under the roundabout so there wasn't a chance for the new road to become an accident blackspot!

They also dropped the speedlimit to 50mph (so you can go faster on the A8 than you can on the new stretch of motorway).

I wrote to the Scottish Executive at the tima and - months later - got a reply telling me they were needed because of the "vertical alignment of the road". I guess that means it goes up/down hill!